JP3384500B2 - Lubricating oil for refrigerator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating machine lubricating oil,
Specifically, a polyoxyalkylene compound having a specific structure is used as a main component, particularly HFC (hydrofluorocarbon).
BON) Lubricating oil for refrigerator useful as a refrigerant.

[0002]

2. Description of the Related Art Due to the problem of ozone layer depletion in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been conventionally used as refrigerants for refrigeration equipment, are subject to regulation. Instead of HFC, HFC (hydrofluorocarbon) is being used as a refrigerant.

Refrigerating machine oil for this HFC refrigerant is H
PAG (Polyalkylene Glycol-compatible with FC)
)), Esters, etc. are being studied or used. For example, regarding PAG, U.S. Pat. No. 4,755,316, JP-A-1-198694, and 1-25659.
No. 4, gazette No. 1-259093, No. 1-22590.
No. 94, No. 1-259095, No. 1-274.
No. 191, No. 2-43290, No. 2-557.
No. 91, No. 2-84491, etc., and regarding esters, publication No. 3-505602, JP-A No. 3-88892, and No. 2-128991.
No. 3,128,992, and No. 3-20089.
5, gazette 3-227397, gazette 4-2059.
No. 7, gazette 4-72390, gazette 4-21859.
No. 2 and No. 4-249593.

However, since PAG has high hygroscopicity and poor electric characteristics (volume resistivity), when used in a hermetic compressor having a structure in which oil and electrodes come into contact with each other, which is used in refrigerators, room air conditioners and the like. There is a risk of leakage.

For this reason, as a hermetic compressor oil for HFC refrigerant, ester oil, which is compatible with HFC, has a lower hygroscopicity than PAG and has excellent electric characteristics, is effective. However, the ester oil may undergo hydrolysis due to its structure and generate an acid, which is expected to cause various inconveniences.

On the other hand, a PAG having low water absorption and high volume resistivity has been proposed (Japanese Patent Laid-Open No. 4-1529).
5, gazette 4-39394, gazette 4-13018.
No. 8). However, this PAG does not fully satisfy all of high compatibility with HFC, low hygroscopicity, and high electric insulation.

[0007]

The present invention is particularly applicable to HFCs.
Excellent compatibility with fluorinated alkane refrigerants such as -134a,
It is an object of the present invention to provide a lubricating oil for refrigerators having low hygroscopicity and excellent electrical characteristics, and a composition for refrigerators using the lubricating oil.

[0008]

Means for Solving the Problems The present inventors have focused their attention on PAGs which have no fear of hydrolysis, and have conducted extensive studies to overcome the above-mentioned drawbacks of PAGs. As a result, polyoxyalkylene compounds having a specific structure HFC, especially HFC-134a
It was found that the compound melts in a wide temperature range, has low hygroscopicity, and has excellent electric characteristics, and has completed the present invention.

That is, the present invention provides the following general formula (1):
1,1-dimethyloxyethylene group represented by:

[0010]

[Chemical 4] And an oxyalkylene group represented by the following general formula (2)

Embedded image Each of —R ¹ —O— (2) (in the above formula (2), R ¹ represents an alkylene group having 2 to 6 carbon atoms excluding the 1,1-dimethylethylene group) in one molecule. It has one or more and is represented by the general formula (2) in the molecule and the number of 1,1-dimethyloxyethylene groups represented by the general formula (1) in one molecule (hereinafter referred to as m). Provided is a refrigerator lubricating oil containing a polyoxyalkylene compound as a main component, in which the number of oxyalkylene groups (hereinafter referred to as n) satisfies the following formulas (A) and (B).

[0011]

[Chemical 6]

The contents of the present invention will be described in more detail below. In the polyoxyalkylene compound according to the present invention, in the oxyalkylene group represented by the general formula (2), which is one of the constitutional units of the polyoxyalkylene portion, R ¹ is an alkylene group having a prime number of 2 to 6 Shows.

Specific examples of R ¹ include ethylene group, propylene group (1-methylethylene group, 2-methylethylene group), trimethylene group, butylene group (1-ethylethylene group, 2-ethylethylene group). ), 1,2-dimethylethylene group, 2,2-dimethylethylene group, 1-
Methyltrimethylene group, 2-methyltrimethylene group, 3
-Methyltrimethylene group, tetramethylene group, pentylene group, (1-butylethylene group, 2-butylethylene group), 1-ethyl-1-methylethylene group, 1-ethyl-2-methylethylene group, 1,1 , 2-trimethylethylene group, 1,2,2-trimethylethylene group, 1-ethyltrimethylene group, 2-ethyltrimethylene group, 3-ethyltrimethylene group, 1,1, -dimethyltrimethylene group, 1, 2-dimethyltrimethylene group, 1,3-dimethyltrimethylene group, 2,3-dimethyltrimethylene group,
3,3-dimethyltrimethylene group, 1-methyltetramethylene group, 2-methyltetramethylene group, 3-methyltetramethylene group, 4-methyltetramethylene group, pentamethylene group, hexylene group (1-butylethylene group, Two
-Butylethylene group), 1-methyl-1-propylethylene group, 1-methyl-2-propylethylene group, 2-methyl-2-propylethylene group, 1,1-diethylethylene group, 1,2-diethylethylene Group, 2,2-diethylethylene group, 1-ethyl-1,2-dimethylethylene group, 1-ethyl-2,2-dimethylethylene group, 2-ethyl-1,1-dimethylethylene group, 2-ethyl- 1,
2-dimethylethylene group, 1,1,2,2-tetramethylethylene group, 1-propyltrimethylene group, 2-propyltrimethylene group, 3-propyltrimethylene group, 1
-Ethyl-1-methyltrimethylene group, 1-ethyl-2
-Methyltrimethylene group, 1-ethyl-3-methyltrimethylene group, 2-ethyl-1-methyltrimethylene group,
2-ethyl-2-methyltrimethylene group, 2-ethyl-
3-methyltrimethylene group, 3-ethyl-1-methyltrimethylene group, 3-ethyl-2-methyltrimethylene group, 3-ethyl-3-methyltrimethylene group, 1,1,
2-trimethyltrimethylene group, 1,1,3-trimethyltrimethylene group, 1,2,2-trimethyltrimethylene group, 1,2,3-trimethyltrimethylene group, 1,
3,3-trimethyltrimethylene group, 2,2,3-trimethyltrimethylene group, 2,3,3-trimethyltrimethylene group, 1-ethyltetramethylene group, 2-ethyltetramethylene group, 3-ethyltetramethylene group Group, 4-ethyltetramethylene group, 1,1-dimethyltetramethylene group, 1,2-dimethyltetramethylene group, 1,3-dimethyltetramethylene group, 1,4-dimethyltetramethylene group, 2,2-dimethyl Tetramethylene group, 2,3-
Dimethyltetramethylene group, 2,4-dimethyltetramethylene group, 3,3-dimethyltetramethylene group, 3,4
-Dimethyltetramethylene group, 4,4-dimethyltetramethylene group, 1-methylpentamethylene group, 2-methylpentamethylene group, 3-methylpentamethylene group, 4-
Examples thereof include a methylpentamethylene group, a 5-methylpentamethylene group and a hexamethylene group.

Further, R ¹ is preferably an alkylene group having 2 to 4 carbon atoms, and an alkylene group having 3 to 4 carbon atoms, specifically, for example, a propylene group (1-methylethylene group,
2-methylethylene group), trimethylene group, butylene group (1-ethylethylene group, 2-ethylethylene group),
1,2-Dimethylethylene group, 2,2-dimethylethylene group, 1-methyltrimethylene group, 2-methyltrimethylene group, 3-methyltrimethylene group, tetramethylene group and the like are more preferable.

The oxyalkylene group represented by the general formula (2) in the polyoxyalkylene compound according to the present invention may be an oxyalkylene group having a single structure, or two or more kinds. The oxyalkylene groups having the structure of may be mixed.

In the polyoxyalkylene compound of the present invention, 1,1 represented by the above general formula (1)
A dimethyloxyethylene group and one or more oxyalkylene groups represented by the above general formula (2) in one molecule, and 1,1-represented by the general formula (1) in one molecule;
When the number of dimethyloxyethylene groups is m and the number of oxyalkylene groups represented by the general formula (2) in one molecule is n, m and n are the following formula (A):

[0017]

[Chemical 7] And the following formula (B):

[Chemical 8] It is important to satisfy both at the same time.

In the polyoxyalkylene compound according to the present invention, when the value of m + n is less than 4, the minimum viscosity required for the lubricating oil for the refrigerator cannot be secured, while when the value exceeds 100, the refrigerant is It is not preferable because it has low compatibility with. When the value of m / (m + n) is less than 0.01, the compatibility with the refrigerant is low,
Alternatively, the hygroscopicity becomes high, while if the value exceeds 0.8, it becomes grease-like at room temperature, which is not preferable.

In the polyoxyalkylene portion of the polyoxyalkylene compound according to the present invention, the 1,1-dimethyloxyethylene group represented by the general formula (1) and the oxyalkylene group represented by the general formula (2) are alternated. , May be bonded randomly, or may be bonded in a block manner. Further, as described above, the oxyalkylene group represented by the general formula (2) in one molecule of the polyoxyalkylene compound according to the present invention may have a single structure, and is included in the general formula (2). To the extent that
An oxyalkylene group having two or more types of structures may be present.

Furthermore, polyoxyalkylene groups having two or more kinds of structures represented by the general formula (2) are present in one molecule of the polyoxyalkylene compound according to the present invention, and are composed of only these oxyalkylene groups. When an alkylene group is present, in this polyoxyalkylene group, two or more types of oxyalkylene groups represented by the general formula (2) may be randomly bonded, or may be bonded in a block manner. Good.

Although the terminal group of the polyoxyalkylene moiety of the polyoxyalkylene compound according to the present invention is optional,
Usually, a hydroxyl group, a monovalent organic residue having 1 to 18 carbon atoms, preferably 1 to 12 or 2 to 20 valent, preferably 2 to 10
It is preferable that the residue is a polyhydric alcohol residue. When one end of the polyoxyalkylene portion of the polyoxyalkylene compound according to the present invention is a residue of a polyhydric alcohol having 2 to 20 valences, the other end group is a hydroxyl group or 1 to 18 carbon atoms. More preferably, it is a valent organic residue.

When both end groups of the polyoxyalkylene moiety are hydroxyl groups or monovalent organic residues having 1 to 18 carbon atoms, the polyoxyalkylene compound according to the present invention is represented by the following general formula (3). it can.

[0023]

[Chemical 9]

In the above formula (3), -X-O- is bonded to the 1,1-dimethyloxyethylene group represented by the formula (1) and the oxyalkylene group represented by the formula (2). A polyoxyalkylene group constituted by the following, and the number (m) of 1,1-dimethyloxyethylene groups represented by the general formula (1) in the group and the oxy represented by the general formula (2). The number (n) of alkylene groups represents a polyoxyalkylene group satisfying the above formulas (A) and (B).

In the above formula (3), R ² and R ³ may be the same or different and each represents a hydrogen atom or an organic residue having 1 to 18 carbon atoms. When R ² and / or R ³ is an organic residue having 1 to 18 carbon atoms,
As the organic residue, for example, those shown below can be preferably used.

Organic residue represented by the following general formula (4):

[Chemical 10]

Organic residue represented by the following general formula (5):

[Chemical 11]

Organic residue represented by the following general formula (6):

[Chemical 12]

In the above formulas (4) to (6), R ⁴ is an alkyl group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms: an alkenyl group having 2 to 18 carbon atoms, preferably 2 to 12 carbon atoms; An aryl group having 6 to 10 carbon atoms, an alkylaryl group, an arylalkyl group; an organic residue in which 1 to 6 hydrogen atoms of these hydrocarbon groups are substituted with a hydroxyl group, an amino group or a cyano group; or these 2 of the hydrocarbon groups of
~ 6 represents an organic residue in which 6 hydrogen atoms have been replaced by epoxy groups.

Specific examples of the group represented by R ⁴ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group and a te group.
rt-butyl group, pentyl group (including all isomers), hexyl group (including all isomers), heptyl group (including all isomers), octyl group (including all isomers), nonyl Group (including all isomers), decyl group (including all isomers), undecyl group (including all isomers), dodecyl group (including all isomers), tridecyl group (all isomers) ,), Tetradecyl group (including all isomers), pentadecyl group (including all isomers), hexadecyl group (including all isomers), heptadecyl group (including all isomers), octadecyl group Alkyl group (including all isomers); vinyl group, propenyl group, isopropenyl group, butenyl group (including all isomers), butadienyl group, pentenyl group (all , Hexenyl group (including all isomers), heptenyl group (including all isomers), octenyl group (including all isomers), nonenyl group (including all isomers) , Decenyl group (including all isomers), undecenyl group (including all isomers), dodecenyl group (including all isomers), tridecenyl group (including all isomers), tetradecenyl group (all isomers) (Including isomers), pentadecenyl group (including all isomers), hexadecenyl group (including all isomers), heptadecenyl group (including all isomers), octadecenyl group (including all isomers), Alkenyl groups such as oleyl groups; phenyl groups,
Aryl group such as naphthyl group; tolyl group (including all isomers), xylyl group (including all isomers), ethylphenyl group (including all isomers), propylphenyl group (including all isomers) Including), ethylmethylphenyl group (including all isomers), trimethylphenyl group (including all isomers), butylphenyl group (including all isomers), methylpropylphenyl group (including all isomers) Including), diethylphenyl group (including all isomers), ethyldimethylphenyl group (including all isomers), tetramethylphenyl group (including all isomers), pentylphenyl group (including all isomers) ), Hexylphenyl group (including all isomers),
Heptylphenyl group (including all isomers), octylphenyl group (including all isomers), nonylphenyl group (including all isomers), decylphenyl group (including all isomers), undecyl Alkylaryl groups such as phenyl group (including all isomers) and dodecylphenyl group (including all isomers); benzyl group, methylbenzyl group (including all isomers), dimethylbenzyl group (all isomers) Body), phenethyl group, methylphenethyl group (including all isomers), dimethylphenethyl group (including all isomers), etc., arylalkyl group; 1 to 6 of these hydrocarbon groups, Preferably, an organic residue in which 1 to 3 hydrogen atoms are substituted with a hydroxyl group, an amino group or a cyano group; or 2 which these hydrocarbon groups have 6, preferably 2 to 4 hydrogen atoms organic residue substituted by an epoxy group such as glycidyl group or glycidyl phenyl group; and the like.

When the compound represented by the above general formula (3) is used as the polyoxyalkylene compound according to the present invention, the terminal groups R ² and R ³ may be the same or different, but the general formula The organic residue represented by (4) is more preferable, and the alkyl group having 1 to 18 carbon atoms is particularly preferable.

Further, one of the terminal groups of the polyoxyalkylene moiety of the polyoxyalkylene compound according to the present invention is 2
When the other end group is a hydroxyl group or a monovalent organic residue having 1 to 18 carbon atoms, the polyoxyalkylene compound according to the present invention has the following general formula: It can be represented by (7).

[0033]

[Chemical 13]

In the above formula (7), --X ₁ --O--, --X ₂ --O
-, ······, -X _a -O-, respectively of the present invention (1)
A polyoxyalkylene group constituted by a bond of a 1,1-dimethyloxyethylene group represented by the formula and / or an oxyalkylene group represented by the formula (2), and in the combination of these oxyalkylene groups The number (m) of 1,1-dimethyloxyethylene groups represented by the general formula (1) and the number (n) of oxyalkylene groups represented by the general formula (2) are the same as the above (A) and (B). The polyoxyalkylene group which satisfy | fills a formula is shown. That is, in the polyoxyalkylene compound represented by the above formula (7) according to the present invention, —X ₁ —O—, —X ₂ —O— ,.
The individual polyoxyalkylene groups represented by X _a —O— do not necessarily have to satisfy the above formulas (A) and (B), and all of these polyoxyalkylene groups are oxy groups which are constituent units thereof. When decomposed into alkylene groups, the total number (m) of 1,1-dimethyloxyethylene groups represented by the general formula (1) and the total number (n) of oxyalkylene groups represented by the general formula (2). Should satisfy the above formulas (A) and (B).

Further, in the formula (7), R ₁ , R ₂ , ..., R _a
May be the same or different and each represents a hydrogen atom or a carbon number of 1 to 18 in the same manner as R ² and R ³ in the formula (3).
A group selected from the organic residues of is shown. Specific examples and preferable examples of these groups include R ² and R ³
And the like listed at the time of the explanation.

In the formula (7), R ⁵ represents a residue of a polyhydric alcohol having a valence of 2 to 20, preferably 2 to 10. When the valence of the polyhydric alcohol residue represented by R ⁵ is c, a and b in the formula (7) are 1 ≦ a ≦ c and 0 ≦ b.
, And a + b = c. Also,
In the present invention, when the polyoxyalkylene compound represented by the formula (7) is used, it is more preferable to use a compound in which b = 0 and a = c.

Specific examples of the polyhydric alcohol residue represented by R ⁵ in the formula (7) include ethylene group, propylene group, trimethylene group, butylene group, 1,1-dimethylethylene group, 1,2 -Dimethylethylene group, 1-methyltrimethylene group, 2-methyltrimethylene group, 2-ethylethylene group, tetramethylene group, 2-propylethylene group, 2-butylethylene group, 2,2-dimethyltrimethylene group, etc. In addition to the dihydric alcohol residue, glycerin, polyglycerin (glycerin 2-18, diglycerin, triglycerin, tetraglycerin, etc.), trimethylolalkane (trimethylolethane, trimethylolpropane, trimethylolbutane, etc.) ) And their 2-3 trimers, monopentaerythritol, dipentaerythritol , Tripentaerythritol, 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol and other polyhydric alcohols, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose. , Mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, merezitose, and other sugars, and their partial etherification products, partial esterification products and polyhydric alcohols such as methyl glucoside (glycoside) Residue (group excluding hydroxyl group from polyhydric alcohol)
Among these, a dihydric alcohol residue, a residue of glycerin or polyglycerin, and a residue of trimethylolalkane and a dimer or trimer thereof are particularly preferred.

The method for producing the polyoxyalkylene compound according to the present invention is arbitrary. Specifically, for example, the polyoxyalkylene compound represented by the general formula (3) is isobutyloxide (1,1- Dimethyl ethylene oxide)
And a total of 4 to 100 mol, preferably 4 to 60, of 1 or 2 or more kinds of alkyleneoside other than the above butylene oxide, which becomes the structure of the general formula (2) when the ring is opened.
It can be obtained by carrying out molar polymerization to form a polyalkylene glycol, or by etherifying, esterifying or carbonic esterifying a part or all of the terminal hydroxyl groups of the polyalkylene glycol thus obtained.

The polyoxyalkylene compound represented by the general formula (7) is specifically, for example, a polyol compound having a valence of 2 to 20 and 1 of the above polyalkylene glycol.
Halogenated with chlorine or bromine at the end, in the presence of alkali such as sodium metal or sodium hydroxide,
It can be obtained by reacting at ˜150 ° C., or by etherifying, esterifying or carbonating some or all of the terminal hydroxyl groups of the polyalkylene glycol chain of the polyoxyalkylene compound thus obtained.

When the polyoxyalkylene compound according to the present invention is produced by these methods, the alkyleneoside, the polyol compound and the polyalkylene glycol may be used either as a single compound or as a mixture of two or more compounds. Good.

As the refrigerating machine lubricating oil according to the present invention, the polyoxyalkylene compound having a single structure according to the present invention may be used in the form of a single product, and polyoxyalkylene having various structures may be used. It may be used in the form of a mixture of compounds or as a single product. Furthermore, the polyoxyalkylene compound according to the present invention may be used in a form in which the reaction product obtained by the reaction as exemplified above is purified and by-products and unreacted substances are removed, but a small amount of by-product The substances and unreacted substances may be present as long as they do not impair the excellent performance of the lubricating oil of the present invention.

The molecular weight of the polyoxyalkylene compound according to the present invention is not particularly limited, but the number average molecular weight is 20 from the viewpoint of further improving the sealing property of the refrigerating compressor.
Those having a number average molecular weight of 300 to 3,000 are more preferably used.
Further, it preferred kinematic viscosity of the polyoxyalkylene compound according to the present invention, 5～2000Mm ² at 40 ° C. /
s, more preferably 7 to 1500 mm ² / s, 1
In 00 ℃ 1.5~100mm ² / s, more preferably from 2 to 50 mm ² / s.

The refrigerator lubricating oil according to the present invention contains the above polyoxyalkylene compound as a main component,
The polyoxyalkylene compound may be used alone or in combination with another refrigerating machine base oil.

The preferred base oil to be mixed is
An oxygen-containing compound, a fluorine-containing compound, and / or a silicon-containing compound as a main component, and specifically, an ester, polyglycol, polyphenyl ether, silicate, polysiloxane, perfluoroether, fluorosilicone, Examples thereof include fluorohydrocarbons, and esters or polyglycols are preferably used.

Specific examples of the ester include dibasic acid ester, polyol ester, complex ester, polyol carbonic acid ester and the like.

Specific examples of the dibasic acid ester include dibasic acids having 5 to 10 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, and methanol, ethanol, Monohydric alcohol having 1 to 15 carbon atoms having a straight or branched alkyl group such as propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc. And an ester thereof are preferably used. Specifically, for example, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di 3
-Ethylhexyl sebacate and the like can be mentioned.

As the polyol ester, an ester of a diol or a polyol having 3 to 20 hydroxyl groups and a fatty acid having 5 to 20 carbon atoms is preferably used.

Here, as the diol, specifically, for example, ethylene glycol, 1,3-propanediol, propylene glycol, 1,2-butanediol,
1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-
2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-
Propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol Etc. On the other hand, as the polyol, specifically, for example, trimethylolethane, trimethylolpropane,
Trimethylol butane, di- (trimethylol propane), tree (trimethylol propane), pentaerythritol, di- (pentaerythritol), tri-
(Pentaerythritol), glycerin, polyglycerin (2 to 20-mer of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, polyhydric alcohol such as mannitol, Sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, and melezitose, and partial etherified products thereof, and methylglucoside ( Glycosides) and the like.

As the fatty acid, specifically, for example,
Pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, oleic acid And straight-chain or branched ones, or so-called neo-acids having a quaternary α carbon atom.

The polyol ester may have a free hydroxyl group. Particularly preferred polyol ester is neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- (pentaerythritol). , Hindered alcohol esters such as tri- (pentaerythritol), and specific examples thereof include trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, and pentaerythritol pelargonate. Can be mentioned.

The complex ester is an ester of a fatty acid and a dibasic acid with a monohydric alcohol and a polyol, and includes a fatty acid, a dibasic acid, a monohydric alcohol,
As the polyol, those similar to those exemplified for the dibasic acid ester and the polyol ester can be used.

The polyol carbonic acid ester is an ester of carbonic acid and a polyol, and the polyol as referred to herein is the same as that exemplified for the polyol ester, a polyglycol obtained by homopolymerizing or copolymerizing a diol, or The above-exemplified polyol to which polyalkylene glycol is added can be used.

As the polyglycol, polyalkylene glycol, etherified products thereof, and modified compounds thereof are preferably used. As the polyalkylene glycol, one obtained by homopolymerizing or copolymerizing a diol is used, and as the diol, the same ones as those exemplified for the polyol ester can be used. Also, ethers of polyalkylene glycol having hydroxyl groups can be used. Specific examples of the etherified product of polyalkylene glycol, monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, monopentyl ether, monohexyl ether, monoheptyl ether, monooctyl ether, monononyl ether, monodecyl ether, Examples thereof include dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether and didecyl ether. Examples of the modified compound of polyglycol include a polyalkylene glycol adduct of polyol, or an etherified product thereof. As the polyol mentioned here, the same ones as those exemplified for the polyol ester can be used. In the polyalkylene glycol, when diols having different structures are copolymerized,
The polymerization mode of the oxyalkylene group is not particularly limited, and may be alternating copolymerization, random copolymerization, or block copolymerization.

When the polyoxyalkylene compound according to the present invention is mixed with the above base oil as the refrigerator lubricating oil according to the present invention and used, the polyoxyalkylene compound according to the present invention is added to the total amount of the lubricating oil. On the other hand, 50% by weight or more,
It is desirable that the content is preferably 70% by weight or more.

Further, the refrigerating machine lubricating oil according to the present invention may be mixed with mineral oil, hydrocarbon-based synthetic oil or the like, if necessary. As the mineral oil, for example, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil,
It is possible to use a base oil such as paraffin-based or naphthenic-based oil that has been refined by appropriately combining refining treatments such as solvent deasphalting, solvent extraction, hydrogenolysis, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment. . Also, as synthetic oil,
For example, poly-α-olefin (polybutene, 1-octene oligomer, 1-decene oligomer, etc.), alkylbenzene, alkylnaphthalene, or a mixture of two or more thereof can be used. However, since these oils have poor compatibility with the refrigerant, the mixing amount is 30% with respect to the total amount of the lubricating oil.
It is desirable that the content is not more than 20% by weight, preferably not more than 20% by weight.

In order to further improve the wear resistance and load resistance of the refrigerator lubricating oil according to the present invention,
At least one phosphorus compound selected from the group consisting of phosphoric acid ester, acidic phosphoric acid ester, amine salt of acidic phosphoric acid ester, chlorinated phosphoric acid ester and phosphorous acid ester can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols, polyether type alcohols, or derivatives thereof. Specific examples of the phosphoric acid ester include tributyl phosphate, triphenyl phosphate, tricresyl phosphate and the like. Examples of the acidic phosphate include ditetradecyl acid phosphate, dipentadecyl acid phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, and the like. The amine salt of acidic phosphoric acid ester includes methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine of the acidic phosphoric acid ester. Dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine,
Examples thereof include salts with amines such as tripentylamine, trihexylamine, triheptylamine and trioctylamine. Examples of the chlorinated phosphoric acid ester include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, tris-chlorophenyl phosphate, polyoxyalkylene bis [di (chloroalkyl)] phosphate and the like. As the phosphite ester,
Dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, diphenyl phosphite, dicresyl phosphite , Tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite, tridodecyl phosphite, triphenyl phosphite , Tricresyl phosphite, and the like. Also, a mixture of these can be used. When these phosphorus compounds are added to the lubricating oil for a refrigerator according to the present invention, the phosphorus compound is contained in a proportion of 0.01 to 5.0% by weight, preferably 0.02 to 3.0% by weight, based on the total amount of the lubricating oil. It is desirable to be strict.

In order to further improve the stability of the lubricating oil for refrigerator according to the present invention, it comprises a phenyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an epoxidized carboxylic acid ester and an epoxidized vegetable oil. At least one epoxy compound selected from the group can be blended. Examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. The alkylphenyl glycidyl ether as used herein has 1 to 3 alkyl groups having 1 to 13 carbon atoms, and particularly 4 to 10 carbon atoms.
Having one alkyl group of, for example, n-butylphenyl glycidyl ether, isobutylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentyl phenyl glycidyl ether, hexyl phenyl glycidyl ether, heptyl phenyl glycidyl ether. , Octyl phenyl glycidyl ether, nonyl phenyl glycidyl ether and decyl phenyl glycidyl ether are preferred. Examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester and the like, and preferable ones are glycidyl hexanoate, glycidyl-2,2-dimethylpentanoate, glycidyl heptanoate, Glycidyl-2,2-
Dimethyl pentanoate, glycidyl octanoate,
Glycidyl-2,2-dimethylhexanoate, glycidyl nonanoate, glycidyl-2,2-dimethylheptanoate, glycidyl-2,2,3,3-tetramethylpentanoate, glycidyl-2,2,3,3 4-tetramethylpentanoate, glycidyl decanoate, glycidyl-2,2-dimethyloctanoate, glycidyl decanoate, glycidyl-2,2-dimethyldecanoate, glycidyl tetradecanoate, glycidyl-2, 2-dimethyl dodecanoate, glycidyl hexadecanoate, glycidyl-2,2-dimethyl tetradecanoate, glycidyl octadecanoate, glycidyl-2,2-dimethyl hexadecanoate, glycidyl eicosanoate, glycidyl- 2,2-dimethyl octadecanoate, Glycidyl benzoate, glycidyl acrylate, glycidyl methacrylate and the like. The epoxidized carboxylic acid ester includes an epoxidized carboxylic acid having 6 to 20 carbon atoms and 1 carbon atom.
Examples thereof include alcohols of 10 to 10 or epoxidized alcohols, esters with phenols and alkylphenols. Especially butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl of epoxystearate,
Phenyl and butyl phenyl esters and esters of epoxidized cyclohexylcarboxylic acid with epoxidized cyclohexylmethyl alcohol are preferably used.
Examples of the epoxidized vegetable oil include epoxy compounds of vegetable oil such as soybean oil, linseed oil and cottonseed oil.

Preferred among these epoxy compounds are phenyl glycidyl ether type epoxy compounds, phenyl glycidyl ester type epoxy compounds and epoxidized carboxylic acid esters. Among them, phenyl glycidyl ether type epoxy compounds and phenyl glycidyl ester type epoxy compounds are more preferable,
Particularly preferred are phenyl glycidyl ether, butyl phenyl glycidyl ether or alkyl glycidyl esters or mixtures thereof. When these epoxy compounds are blended with the lubricating oil for a refrigerator according to the present invention, the proportion thereof is 0.01 to 5.0% by weight, preferably 0.02 to 3.0% by weight, based on the total amount of the lubricating oil. It is desirable to include it.

Further, in the lubricating oil for a refrigerator according to the present invention, in order to further improve its wear resistance and load resistance, an aliphatic monocarboxylic acid having 8 to 18 carbon atoms and / or 5 to 18 carbon atoms. The aliphatic dibasic acid can be added.

Specific examples of the aliphatic monocarboxylic acid and / or aliphatic dibasic acid include octanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, Heptadecanoic acid, stearic acid, oleic acid, nonadecanoic acid, eicosanoic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, octylmalonic acid, nonylmalonic acid, decylmalonic acid, undecylmalonic acid, dodecylmalon Acid, tridecyl malonic acid,
Examples thereof include tetradecylmalonic acid, pentadecylmalonic acid, hexadecylmalonic acid, heptadecylmalonic acid, octadecylmalonic acid, and mixtures of two or more thereof. When these aliphatic monocarboxylic acids and / or aliphatic dibasic acids are blended, it is preferable that the total amount of lubricating oil is 0.
It is desirable that the content of Si is 0.1 to 3% by weight, preferably 0.05 to 2% by weight.

It is needless to say that two or more kinds of the above phosphorus compound, epoxy compound and aliphatic monocarboxylic acid and / or aliphatic dibasic acid may be used in combination.

Further, in order to further enhance the performance of the refrigerator lubricating oil according to the present invention, conventionally known additives for refrigerator oils, such as di-tert-butyl-p-cresol and bisphenol, are used, if necessary. Phenolic compounds such as A, phenyl-α-naphthylamine, N, N′-di (2
-Naphthyl) -p-phenylenediamine and other amine-based antioxidants, zinc dithiophosphate and other antiwear agents, chlorinated paraffins, sulfur compounds and other extreme pressure agents, fatty acids and other oil-based agents, silicone-based and other antioxidants Additives such as a foaming agent, a metal deactivator such as benzotriazole, a viscosity index improver, a pour point depressant, and a detergent dispersant can be blended alone or in combination of several kinds. The total blending amount of these additives is usually 10% by weight or less, preferably 5% by weight or less, based on the total amount of the lubricating oil.

The refrigerator lubricating oil containing a polyoxyalkylene compound as a main component according to the present invention may have a pour point that is generally used as a refrigerator oil.
In order to prevent the solidification of the lubricating oil at low temperature, the pour point is -10.
It is desirable that the temperature is not higher than ℃, preferably -20 ℃ to -80 ℃.

Examples of the refrigerant used in the refrigerator using the lubricating oil for refrigerator according to the present invention include fluoroalkanes and / or chlorofluoroalkanes having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms.

Specifically, for example, difluoromethane (H
FC-32), trifluoromethane (HFC-23),
Pentafluoroethane (HFC-125), 1,1,
2,2-tetrafluoroethane (HFC-134),
1,1,1,2-Tetrafluoroethane (HFC-13
4a), 1,1,2-trifluoroethane (HFC-1
43), 1,1,1-trifluoroethane (HFC-1
43a), 1,1-difluoroethane (HFC-152
a), Monochlorodifluoromethane (HCFC-2
2), 1-chloro-1,1-difluoroethane (HCF
C-142b), dichlorotrifluoroethane (HCF
C-123), monochlorotetrafluoroethane (HC
FC-124) and other hydrogen-containing CFCs, hydrogen such as trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), monochlorotrifluoromethane (CFC-13) and monochloropentafluoroethane (CFC-115). Examples of the non-containing CFC, or a mixture of two or more thereof, include hydrogen-containing CFCs, particularly HFC-32 and HFC-2, from the viewpoint of environmental problems.
3, HFC-125, HFC-134, HFC-134
a, HFC-143, HFC-143a, HFC-15
It is preferable to use hydrogen-containing non-chlorine-based CFCs such as 2a.

These refrigerants are appropriately selected according to the intended use and the required performance, for example, HFC-134a alone; HFC
-134a is 60-80% by weight and HFC-32 is 40-
20% by weight mixture; 60% by weight HFC-134a, 30% by weight HFC-32 and 10% by weight HFC-125; and 52% by weight HFC-143a and H.
A mixture of 44% by weight of FC-125 and 4% by weight of HFC-134a may be mentioned.

The refrigerating machine lubricating oil according to the present invention is usually in the form of a refrigerating machine composition which is mixed with a fluoroalkane and / or a chlorofluoroalkane which is a CFC refrigerant in the refrigerator. Exists in. The blending ratio of the refrigerator lubricating oil and the refrigerant in this composition is arbitrary, but normally, the refrigerator lubricating oil 1 to 100 parts by weight of the refrigerant is used.
˜500 parts by weight, preferably 2 to 400 parts by weight.

The lubricating oil for refrigerators and the composition for refrigerators of the present invention are particularly preferably used for air conditioners and refrigerators having reciprocating or rotary hermetic compressors because of their excellent electric characteristics and low hygroscopicity. To be Further, it is particularly preferably used for a vehicle air conditioner, a dehumidifier, a freezer, a refrigerating / freezing warehouse, a vending machine, a showcase, a cooling device for a chemical plant and the like. Further, it is also preferably used for those having a centrifugal compressor.

[0069]

EXAMPLES The contents of the present invention will be described more specifically below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 22.44 g (0.2 mol) of potassium t-butoxide was placed in a 300 ml stainless steel autoclave equipped with a stirrer, a pressure gauge, a temperature measuring tube, and a liquid introducing tube, which was hermetically closed to reduce the pressure. Then, 100 ml of dehydrated toluene was inhaled. Stirring was started and heated to 120 ° C. Into this, 144 g of a mixed solution of isobutylene oxide and 1,2-butylene oxide (molar ratio 3: 1) was introduced by a pump over 5 hours. After completion of the introduction, the autoclave was further matured at 120 ° C. for 1 hour and then cooled in ice water. When the temperature inside the autoclave fell below 10 ° C, 56 g of methyl iodide
(0.4 mol) was injected. While stirring, the mixture was gradually heated and reacted at 90 ° C. for 3 hours. After cooling with ice water, the autoclave was disassembled and washed with 500 ml of toluene in an 11-minute separating funnel. After washing twice with 250 ml of pure water,
It was treated with dilute hydrochloric acid and further washed with 250 ml of pure water until it became neutral. After dehydrating the toluene solution with anhydrous sodium sulfate, most of the toluene was previously removed with a rotary evaporator, and then 0.1 mm was obtained using a vacuum pump.
It was distilled under reduced pressure for 1 hour under the condition of Hg or less and 100 ° C. This was stirred at 60 ° C. for 1 hour together with 5 g of dehydrated low temperature activated clay, and the clay was filtered off. The target product thus obtained was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.

Example 2 21.04 g (0.3 mol) of potassium methoxide was used in place of potassium t-butoxide, and 144 g of a mixed solution of isobutylene oxide and 1,2-butylene oxide (molar ratio 3: 2) was used. The target product was obtained in the same manner as in Example 1 except for the above. The obtained target product was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.

Example 3 The object product was obtained in the same manner as in Example 1 except that 144 g (molar ratio 1: 1) of a mixed solution of isobutylene oxide and 1,2-butylene oxide was used. The obtained target product was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.
It was shown to.

Example 4 14.03 g (0.2 mol) of potassium methoxide was used instead of potassium t-butoxide, and 144 g of a mixed solution of isobutylene oxide and 1,2-butylene oxide (molar ratio 3: 2) was used. The target product was obtained in the same manner as in Example 1 except for the above. The obtained target product was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.

Comparative Example 1 Commercially available polypropylene glycol monomethyl ether was used. The structure and properties are shown in Table 1.

Comparative Example 2 Commercially available polypropylene glycol dimethyl ether was used. The structure and properties are shown in Table 1.

Comparative Example 3 Only isobutylene oxide (144 g) was used instead of the mixed solution of isobutylene oxide and 1,2-butylene oxide.
The target product was obtained in the same manner as in Example 1 except that was used. The target product obtained was in the form of grease.

Comparative Example 4 Potassium methoxide (14.03 g, 0.2 mol) was used instead of potassium t-butoxide, and only 1,2-butylene oxide was used instead of a mixed solution of isobutylene oxide and 1,2-butylene oxide. The target product was obtained in the same manner as in Example 1 except that (144 g) was used. The obtained target product was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.

Comparative Example 5 21.04 g (0.3 mol) of potassium methoxide was used instead of potassium t-butoxide, and only 1,2-butylene oxide was used instead of a mixed solution of isobutylene oxide and 1,2-butylene oxide. The target product was obtained in the same manner as in Example 1 except that (144 g) was used. The obtained target product was a colorless transparent liquid. The structure and properties of this liquid are shown in Table 1.

Table 1 shows the structure and properties of the polyoxyalkylene compound refrigerator lubricating oil obtained by the above method and having the following structure.

[0080]

[Chemical 14]

(In the above formula, -X-O- represents (1) of the present invention.
A 1,1-dimethyloxyethylene group represented by the formula and a oxyalkylene group represented by the formula -R ¹ -O-= (2), which is a polyoxyalkylene group formed by bonding, and In the group, the number of 1,1-dimethyloxyethylene groups represented by the general formula (1) is m, and the number of oxyalkylene groups represented by the general formula (2) is n. )

[0082]

[Table 1]

The polyoxyalkylene compounds of Examples and Comparative Examples were subjected to the following performance evaluation test as a lubricating oil for refrigerators, and the results are shown in Table 2.

[High-temperature two-layer separation temperature with HFC-134a] 0.15 g of the polyoxyalkylene compounds of Examples and Comparative Examples were collected in a pressure resistant glass tube having a capacity of 10 ml.
Further, 4.85 g of the refrigerant (HFC-134a) (polyoxyalkylene compound / polyoxyalkylene compound +
Refrigerant = 3% by weight) was sampled, and this glass tube was placed in a constant temperature bath at a predetermined temperature to observe whether the refrigerant and the polyoxyalkylene compound were mutually dissolved, separated or clouded.

[Low temperature two-layer separation temperature with HFC-134a] According to JIS K 2211 4.12, 5 g of the polyoxyalkylene compounds of Examples and Comparative Examples were collected, and 20 g of refrigerant (HFC-134a) (polycarbonate) was used. Oxyalkylene compound / Polyoxyalkylene compound +
Refrigerant = 20% by weight) was sampled, and it was observed whether the refrigerant and the sample oil were mutually dissolved, separated or clouded.

[Hygroscopicity] 20 g of the polyoxyalkylene compound of Examples and Comparative Examples was used, and the inner diameter was 30 mm and the depth was 60 m.
m glass container, temperature 25 ℃, relative humidity 80%
The sample was placed in a constant temperature and constant humidity tank of No. 1 to absorb moisture, and the amount of water was measured by a Karl Fischer moisture measuring device (CA06 type manufactured by Mitsubishi Kasei Co., Ltd.).

[Volume Resistivity] According to JIS C 2101, the volume resistivity of the polyoxyalkylene compounds of Examples and Comparative Examples at 25 ° C. was measured.

[0088]

[Table 2]

[0089]

As is clear from the above, the lubricating oil for a refrigerator containing the polyoxyalkylene compound according to the present invention as a main component is compatible with a refrigerant, particularly a fluoroalkane refrigerant, in a wide temperature range, It has low hygroscopicity, excellent electrical properties, and there is no concern about hydrolysis.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Suda 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Nihon Sekiyu Co., Ltd. Central Research Laboratory (56) Reference Japanese Patent Laid-Open No. 4-130188 (JP, A) Kaihei 4-39394 (JP, A) JP-A-4-15295 (JP, A) JP-A-3-205492 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C10M 105 / 18 C10M 107/34 C10N 40:30 C09K 5/04

Claims (2)

(57) [Claims] 1. A 1,1-represented by the following general formula (1):
Dimethyloxyethylene group: And an oxyalkylene group represented by the following general formula (2): embedded image —R ¹ —O— (2) (In the above formula (2), R ¹ is a carbon excluding a 1,1-dimethylethylene group. The number of 1,1-dimethyloxyethylene groups represented by the general formula (1) in one molecule (hereinafter, m). And the number of oxyalkylene groups represented by the general formula (2) in the molecule (hereinafter, n) satisfies the following formulas (A) and (B). Lubricating oil for machines. [Chemical 3] 2. A refrigerator composition comprising (I) a mixture of the polyoxyalkylene compound according to claim 1 and (II) a fluorinated alkane and / or a chlorofluoroalkane.